Em Thu, Oct 03, 2013 at 01:58:11PM +0530, Ramkumar Ramachandra escreveu:
> Currently, execution of 'perf trace' reports the following cryptic
> message to the user:
> 
> $ perf trace
> Couldn't read the raw_syscalls tracepoints information!
> 
> Now, it prints a detailed message:

What about the one attached instead? It 

[acme@zoo ~]$ mount | grep debugfs
[acme@zoo ~]$ 
[acme@zoo ~]$ perf trace usleep 1
Is debugfs mounted? Try 'sudo mount -t debugfs nodev /sys/kernel/debug'
[acme@zoo ~]$ sudo mkdir /d
[acme@zoo ~]$ sudo mount -t debugfs nodev /d
[acme@zoo ~]$ mount | grep debugfs
nodev on /d type debugfs (rw,relatime)
[acme@zoo ~]$ 
[acme@zoo ~]$ perf trace usleep 1
Couldn't access debugfs. Try 'sudo mount -o remount,mode=755 /d'
[acme@zoo ~]$ sudo mount -o remount,mode=755 /d
[acme@zoo ~]$ perf trace -e mmap usleep 1
     0.956 ( 0.004 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46dfc000
     0.995 ( 0.004 ms): mmap(len: 125871, prot: READ, flags: PRIVATE, fd: 3                   ) = 0x46ddd000
     1.045 ( 0.005 ms): mmap(addr: 0x3da4800000, len: 2135088, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) = 0xa4800000
     1.068 ( 0.005 ms): mmap(addr: 0x3da4a08000, len: 8192, prot: READ|WRITE, flags: PRIVATE|DENYWRITE|FIXED, fd: 3, off: 32768) = 0xa4a08000
     1.109 ( 0.005 ms): mmap(addr: 0x3d93400000, len: 3896312, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) = 0x93400000
     1.125 ( 0.006 ms): mmap(addr: 0x3d937ad000, len: 24576, prot: READ|WRITE, flags: PRIVATE|DENYWRITE|FIXED, fd: 3, off: 1757184) = 0x937ad000
     1.134 ( 0.004 ms): mmap(addr: 0x3d937b3000, len: 17400, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS|FIXED, fd: 4294967295) = 0x937b3000
     1.147 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46ddc000
     1.160 ( 0.003 ms): mmap(len: 8192, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46dda000
[acme@zoo ~]$